本文于2017年11月22日发表于Plant Physiology，通讯作者为中国农业大学毛同林教授，原文题目为：

Coordinated Regulation of Hypocotyl Cell Elongation by Light and Ethylene through a microtubule destabilizing protein

下胚轴细胞伸长的精确调节对于植物生长和存活至关重要。光通过降解转录因子PIF3来抑制下胚轴伸长，而植物激素乙烯则通过激活PIF3促进下胚轴伸长。然而，关于这两条途径如何协调下游效应子介导下胚轴伸长的基本机制在很大程度上还不清楚。在这项研究中，我们确定了一个新的蛋白MDP60，它在拟南芥下胚轴细胞伸长中起着正调控作用；这种作用是通过PIF3介导的。乙烯信号通过PIF3与MDP60启动子的结合来上调MDP60的表达。与对照相比，MDP60功能缺失的突变体显示出更短的下胚轴，而MDP60过表达在光下生长时可以显著的促进下胚轴细胞伸长。MDP60蛋白在体外和体内均与微管结合。在mdp60突变细胞和MDP60过表达的幼苗中，皮质微管的组织显著被破坏。这些发现表明MDP60是下胚轴细胞伸长的重要的调控子。这项研究揭示了一个机制，拟南芥中，光和乙烯信号通过改变皮质微管，协调MDP60的表达来调节下胚轴细胞伸长。

Precise regulation of hypocotyl cell elongation is essential for plant growth and survival. Light suppresses hypocotyl elongation by degrading transcription factor phytochrome-interacting factor 3 (PIF3), whereas the phytohormone ethylene promotes hypocotyl elongation by activating PIF3. However, the underlying mechanisms regarding how these two pathways coordinate downstream effectors to mediate hypocotyl elongation are largely unclear. In this study, we identified the novel Microtubule-Destabilizing Protein 60 (MDP60), which plays a positive role in hypocotyl cell elongation in Arabidopsis; this effect is mediated through PIF3. Ethylene signaling up-regulates MDP60 expression via PIF3 binding to the MDP60 promoter. MDP60 loss-of-function mutants exhibit much shorter hypocotyls, whereas MDP60 overexpression significantly promotes hypocotyl cell elongation when grown in light, as compared to the control. MDP60 protein binds to microtubules in vitro and in vivo. The organization of cortical microtubules was significantly disrupted in mdp60 mutant cells and MDP60-overexpressing seedlings. These findings indicate that MDP60 is an important mediator of hypocotyl cell elongation. This study reveals a mechanism in which light and ethylene signaling coordinate MDP60 expression to modulate hypocotyl cell elongation by altering cortical microtubules in Arabidopsis.

每日一词：

cortical 英['kɔ:tɪkl] 美['kɔ:tɪkl]

adj. 皮层的，皮质的，有关脑皮层的;

[例句]In experiments, using this model we simulated the spiking and bursting behavior of known types of cortical neurons.

在实验中，应用该模型模拟了大部分已知皮层神经元的脉冲和簇放电行为。

编译者：植物科学SCI